1. Field of the Invention
The present invention relates to a regulator for use with a fuel cell for supplying an anode of a fuel cell stack with a fuel (hydrogen) as a reactant gas under a pressure depending on the pressure of an oxidizing agent (air) which is given as a signal pressure.
2. Description of the Related Art
Heretofore, solid polymer membrane fuel cell have a stack of cells (hereinafter referred to as a fuel cell stack) each comprising an anode and a cathode and a solid polymer electrolyte membrane interposed between the anode and the cathode. When hydrogen is supplied as a fuel to the anode and air is supplied as an oxidizing agent to the cathode, hydrogen ions are generated at the anode by a catalytic reaction. The hydrogen ions move through the solid polymer electrolyte membrane to the cathode. Electric power is generated in the fuel cell by the electrochemical reaction.
The fuel cell system includes an air compressor for supplying air as a reactant gas to the cathodes of the fuel cell stack and a pressure control valve for supplying hydrogen as a reactant gas to the anodes of the fuel cell stack under a pressure depending on the pressure of air which is given as a signal pressure. The pressure of the reactant gas supplied to the anodes with respect to the pressure of the reactant gas supplied to the cathodes is adjusted to a predetermined pressure for thereby achieving a predetermined power generation efficiency, and the flow rate of the reactant gas supplied to the fuel cell stack is controlled to obtain a desired fuel cell output.
The applicant of the present application has proposed a gas pressure reducing valve for use in a fuel gas supply device, as disclosed in Japanese laid-open patent publication No. 2002-182751 and Japanese laid-open patent publication No. 11-270717.